Trigger mechanism for automatic firearms



Oct. 10, 1944. J. VESELY TRIGGER MECHANISM FOR AUTOMATIC FIREARMS Original Filed March 4, 1942 V9 5 el Invenlor v Q Attorney Patented Oct. 10, 1944 TRIGGER MECHANISM FOR AUTOMATIC FIREARMS Josef Veseli Winchmore Hill, London, England Original application March 4, 1942, Serial No. 433,322. Divided and this application July 1'7, 1943, Serial No. 495,096. In Great Britain June 1 Claim.

This invention concerns trigger mechanism for automatic firearms characterised in that the trigger carries a pivotal tripping link adapted to actuate a pivotal sear co-operating with a shoulder in the breech block, such link being capable of being set by a manually operable regulator ,in any one of three different positions and according to its setting ensuring respectively that (a) the gun will fire continuously whilst the trigger remains pulled (this is hereinafter referred to as the continuous firing position); (b) the gun will fire only a single shot each time the trigger is pulled (this is hereinafter referred to asthe single shot position); and (c) that operation of the trigger will not operate the sear (this is hereinafter referred to as the safety position); such tripping link being adapted to engage and to move the sear to release the breech block on the trigger being pulled when the link is set to attain either of conditions (a) and (b) but being adapted to pass inoperatively through an opening in the sear on the trigger being pulled when the tripping lever is set to attain condition and such tripping link also having an extension adapted to co-operate with the breech block when the link is set to attain condition (1)) so that as the breech block recoils (after a shot has been fired) it operates the tripping lever to release the sear for engagement with the breech block to lock this against another forward movement until the trigger is pulled again, this application being a division of application Serial No. 433,322, filed March 4, 1942.

According to one aspect of this invention there is provided a trigger mechanism having the above specified characteristics and wherein the said tripping link does not normally pass through the hole in the sear but only enters this hole when in the safety position, such link being adapted, when in its continuous firing or single shot positions and when the trigger is pulled, to act with a pushing action upon the surface of the sear nearest the trigger, and wherein the said regulator comprises a lever or cam mounted on the same pivoting axis as the scar and adapted to engage the tripping link between the extension and the sear engaging end of the link.

The accompanying drawing shows by way of example one embodiment of the invention:

Figure 1 shows the trigger mechanism in the automatic or continuous firing position;

Figure 2 shows the trigger mechanism in the safety position;

Figure 3 shows the trigger mechanism in the single shot position;

Figure 4 is a sectional side elevational view of a gun provided with the trigger mechanism according to this invention.

The gun to which the invention is applied may 5 be of any desired design, but for the purpose of explaining the invention the type of gun illustrated in Figure 4 has been chosen. 7

This gun comprises a barrel I, surrounded by a cooling jacket 2, this barrel being rigidly con- 10 nected with a gun body 3 which is of circular form in -cross-section. The usual rearsight 4 is secured to the gun body 3 and provision is made in the lower part of the gun body for attaching a magazine 5 of any suitable design. For

example, a holder 6 may be provided at the lower side of the gun body 3 to receive the magazine 5 which is held in the holder by a suitable catch 1.

The gun body is rigidly, but removably, connected at its rear end to a butt holder 8, which holder is in turn connected with a butt 9 of any convenient known form. The butt holder 8 accommodates the trigger mechanism, indicated generally by H! in Figure 4. a

A breech block guide ll of generally semicircular form in cross-section is mounted within the gun body 3, for co-operation with a breech block l2 forming part of a breech action. The breech block I2 is of semi-cylindrical form to fit the interiorvof the gun body when mounted on the breech block guide ll therein.

The breech block I2 is provided on its underside with a longitudinally and downwardly extending projection 30 having an inclined front end 3| with which the sear 2| of the trigger mechanism (to be described hereinafter) is adapted to engage, and at some distance behind the said inclined surface 3| the projection 30 is provided on its underside with a notch or recess 32 with which an extension [9 of a tripping lever I I (both subsequently described) is adapted to co-operate.

The trigger mechanism (Figures 1 to 3) comprises a trigger lever I4 mounted, inmrmediate its ends, on a pivot l5 in a casing l6 which forms a housing for all parts of the trigger mechanism. One end of the trigger lever I4 is pivotally connected at Ma with one end of a tripping lever or interrupter H, the other end of which is free and is permanently biased upwards by a tension spring I8 extending between the tripping lever and an anchorage lBa on the casing.

The extension [9 has an arcuate upper end and is provided on the upper side of the tripping lever I1. In a given position of the tripping lever the extension l9 lies inrthe path of the projection 30 of the movable breech block l2, the arrangement being such that the latter, during its movement, may depress the tripping lever H in the manner and for the purpose to be described.

A lateral projection 20 is provided on one side of the free end of the tripping lever II, this projection being capable, according to the position of the tripping lever l1, either of engaging the surface of one arm of the two armed pivoted sear 2| or of passing freely through an opening or a slot 22 formed in such arm.

The sear 2| mounted on a pivot 25 is biased, counter-clockwise as seen in the drawing, by a spring 23 so that the upper end of the sear is urged upwards into the path of the front end 3| o of the shoulder 30 on the breech block soas to engage such shoulder in front of the notch 32.

for firing. However, in this third position of the tripping lever 11, the extension 19 on the latter lies in the path of the breech block I2, so that the latter brings about depression of the tripping lever II. In the depressed position of lever I! the projection 20 thereon is opposite the slot 22 7 again. In this position, therefore, the gun is set for single shots. 7 I

In an automatic firearm, means for setting the I firearm selectively in continuous firing, single shot A safety and adjusting lever 24 is pivotally mounted in the trigger housing ||l on the same pivot 25 as the sear. This lever 24 is arranged to engage co-operatively with the free front end of the tripping lever I! and can be'adjusted from the exterior of the casing by a suitable lever 26 (Figure 1) between three positions in each of which it is held by a spring loaded ball orpin such as that shown 'at 21 (Figure 1).

According to the setting of the levers 26 and 24 the fore end of the tripping lever I! will assume one of-three different positions.

In the first or continuous firing position shown in Figure 1, the fore end of tripping lever I7 is held depressed by the lever 24. In this position,

firin'g, or non-firing or safety condition, such means comprising in combination a reciprocable breech block provided on its underside with a projection having a recess between its ends, a casing adapted for mounting on the firearm, and trigger mechanism carried by said casing, such trigger mechanism comprising a two-armed pivoted sear having its upper arm spring urged into the path of movement of the front 'end of the said prolectio'no'n the breech block, and having its lower arm extending downwardly from the pivot of the if the trigger lever H is pulled, the projection 20 v on the tripping lever 11 strikes the lower end of the sear 2| and swings the latter about its pivot in a clockwise direction and its upper end is moved out of engagement with inclined surface 3| of thebreech block l2 which then becomes free to move forwards under the influence of a recoil spring l3 and subsequently backwards under the influence of the recoil forces, without being arrested by the sear 2| which remains in the disengaged position until the trigger is released.

In the second or safety position shown in Figure 2, the tripping lever I! is in an intermediate position in which the lateral projection 20 on the lever is opposite the slot 22 in the sear. If the trigger lever I4 is pulled, the projection 20 passes through the slot 22 without touching the sear 2| so that the breech block ,|2 is not released for the firing operation. p r V 1 In the third or singleshot position shown in Figure 3 the tripping lever I1 is set in its uppermost position. If now the trigger is pulled, the lateral projection 20 on the tripping lever I'l en gages the sear 2| to release the breech block l2 sear-and provided withan opening therethrough, a pivoted Ytrigger lever, a floating tripping link pivoted at its rear end to the 'upper'en'd of the said trigger lever and spring urged towards the said breech block. an upwardextension on; and

between the ends of, the said tripping lever, such extension being adapted to co-operate with the said recess in the breech block projection when the tripping lever isset in its uppermost single shot firing position, a lateral projection on the front free end of' the tripping link and adapted, according to the setting of the tripping lever, to enga e the lower arm of the said sear either above or below'the opening therein,-or to register with the opening in such arm for passage therethrough, said lateral projection being adapted, in its upper or lower position, to operate with a pushing action on that side of the lower sear arm nearest the trigger'when the latter is pulled, or to pass into and through the opening in the said lower sear arm only when the lateral projection is in its intermediate position and on the trigger being pulled, and a pivoted tripping-link-adjusting-member mounted on the same pivoting axis as the said sear and adapted to engage the tripping lever between its upward extension and its lateral projection for setting the tripping lever in any of its several adjusted positions.

J'OSEF vEsELY. 

